Wireless telecommunications networks are constantly evolving. As wireless telecommunications technologies proliferate, new base stations are installed to provide service to an ever increasing number of users that use an increasing amount of data. In addition, existing base stations are serviced to maintain and upgrade the existing sites.
The installation and maintenance of base stations is performed by trained and skilled personnel. However, cellular equipment is highly complex, and is not typically designed for ease of installation. Errors are made when installing and maintaining base station equipment that result in compromised performance.
While some technician errors are easy to detect and resolve, other errors are more difficult to detect. One error that occurs in networks is a crossed, or incorrect antenna feed at a cell-site.
In a cellular network, each cell-site may house multiple cells belonging to different frequencies and technologies. For a specific frequency and technology, a site could also have multiple cells. These may correspond to different sectors and may be intended to provide coverage along different directions using antennas pointed in these different directions.
Each cell-site has one or more antennas. The antennas may point in different directions. These antennas may also be used for transmit and/or receive purposes.
Each cell has one or more antenna feeders. Antenna-feeders from cells need to be connected to the correct antenna at the cell-site. The term correct antenna refers to an antenna pointing in the direction intended for the cell and/or intended purpose of the antenna feeder, which may be to transmit or receive. The installation is further complicated by the fact that may be multiple cells per antenna (belonging to different frequencies or technologies). Feeders from multiple cells may be combined into one physical cable which feeds the antenna by using an RF combiner.
Crossed feeders could happen in multiple ways including between sectors or between transmit and receive antennas at sectors. The crossed feeders can also occur at multiple locations in the set-up, including before or after the RF combiner.
When a crossed antenna feed is present, instructions for a target antenna are incorrectly delivered to a crossed antenna. As a result, some of the actual configuration parameters of cells (e.g. antenna pointing direction and antenna elevation) at these sites will be different from the planned configuration of the cells. This may lead to unexpected behavior of network performance management operations such as capacity and coverage optimization, cell outage compensation etc., which rely on accurate cell configuration information.
In most scenarios, the manifestation of a crossed-antenna on network performance is such that it is not easy to directly deduce the root-cause of the issue as being a crossed-antenna feeder. For example, a crossed-antenna issue at a cell-site could result in poor scrambling-code disambiguation. However, it is not easy to map this issue to a crossed-antenna feeder at a particular site. Furthermore, in the case of new base stations, there is no control data, so it is difficult to differentiate a potential crossed antenna feed from other variables that can affect performance.
Network operators are aware of the potential issues related to a crossed antenna feed. Conventionally, drive tests are conducted to compare antenna configuration data to actual measured data. In a drive test, a technician will drive to specific geographic areas measure cell characteristics. However, drive tests are expensive, time consuming, and error prone. Networks would benefit from a system and method that reliably detects crossed antenna feeds, as well as a system and method that automates at least some portion of crossed antenna feed detection.